CA1296671C

CA1296671C - Conveyor belt and system with a non-collapsing inside edge

Info

Publication number: CA1296671C
Application number: CA000574051A
Authority: CA
Inventors: Gerald C. Roinestad; Michael Robert Straight
Original assignee: Ashworth Bros Inc
Current assignee: Ashworth Bros Inc
Priority date: 1987-08-10
Filing date: 1988-08-05
Publication date: 1992-03-03
Anticipated expiration: 2009-03-03
Also published as: JPH0767963B2; KR890003607A; DE3888753D1; ATE103567T1; KR970011925B1; DE3888753T2; EP0303457A1; EP0303457B1; JPH01139409A

Abstract

ABSTRACT OF THE DISCLOSURE
A conveyor belt and conveying system designed to operate about lateral curves is disclosed. The conveyor belt is comprised of transverse rods interconnected by links disposed along opposite trans-verse edges of the belt. When the belt proceeds about a lateral curve, the pitch along the inside edge of the curve is kept substantially the same as in straight line motion, while the outside edge of the belt is allowed to expand to a second greater pitch. In one embodiment sup-port links are disposed along the inside edge of the belt and provide support for the inside edge of successive tiers of the belt as the belt travels a helical path. A specific link construction which uses a worked hardened bearing surface is also disclosed.

Description

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CONVEYOR BELT AND SYSTEM WITH A
NON-COLLAPSING INSIDE ED~3E

T~CHNICAL FIELD
This invention relates to a conveyor belt and system designed to travel about lateral curves. More specifically, the invention con-cerns a conveyor belt which includes transverse rods connected by links disposed along the opposite transverse ends of the rods, wherein the insi~e ends of the rods along the inside edge of the belt are kept at a constant first pitch and the outside ends of the rods are allowed to move to a second larger pitch.
BAÇKGROUND OF THE INVENTION
Conveyor belts comprised of transverse rods connected by links disposed along the opposite transverse edges of the belt have been in use for a long period of time. One such prior art belt uses generally U-shaped nestable links with slotted holes that allow the links to slide on the rods. The relative sliding action between the links and rods provides lateral flexibility which enables the belt to turn right or le~t, when such nestable links are used on both sides of the belt. Wh~n such a belt proceeds around a lateral curve, the rod ends along the inslde concave edge of the belt collapse. The opposite transverse end~ of the rods along the outside convex edge df the belt either remain at the same pitch as when the belt travels in a straight line direction, such as disclosed in U.S. Patent No. 3,225,898 to Rolnestad, or expand to a greater pitch in order to allow the belt to proceed around a smaller radius, as disclosed in U.S. Patent No. 4,078,655 to Roinestad.
The collapsing or diminishing pitch of the belt along the inside edge of a lateral curve creates several problems. First of all, most ware i5 charged into a conveying systern in a rank and file arrange-ment, and spacing of the ranks (crosswise rows) can only be controlled by adjusting the relative speeds of the individual feed conveyors. To make certain that the ware does not overlap, it is necessary to take into account the collapsing pitch and to also leave a safety margin in the spacing, both of which result in a clrop in efficiency. If the ware being conveyed is soft in nature, the collapsing pitch can result in wrinkling of the ware. Also, if the conveyor is used in a freezing plant, the collapsing pitch can result in contact and freezing together of adjacent wara if sufficient spacing is not used.
U.S. Patsnt No. 4,662,509 issued to Kaak on May 5, 198~
addresses the problem of a conveyor belt having a collapsing inner edge in a chain type conveyor belt wh0rein the ware support carriers are connected directly to a drive chain. The chain conveyor belt in the ~S09 patent uses triangular carriers consisting of a rod-shaped element and a pulling element. Along the inside edge of the conveyor belt, the rod-shaped element and the pulling element are pivotably connected to the drive chain, and the pitch of the rod-shaped ele-ments is held constant by the connection to the drive chain. The pull-ing elements slant backward in the direction of travel of the belt and are pivotably connected to one of the rod-shaped elements further rearward along the belt. As the belt proceeds around a curve, the outside, free ends of the rod shaped elements increase their spacing or pitch with respect to one another.
The conveyor belt disclosed ln the 'S09 patent, however, has certain disadvantages or limitations. The triangular configuration of the ware carriers preclude~ negotiation about end pulleys or rolls, or operating through a vertical hanging take-up mechanism. The practi-cal width of the ware carriers is limited by the triangular configura-tion, hecause the effectiveness of the pulling element dirninishes with increasing ~vidth. Finally, ~he overlapping orientation of the pulling and rod-shaped elements gives rise to serious sanitation difficulties.
The capabillty to clean between all elements of a belt is important when the conveyor belt is used in a food handling environment.

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It has also been discovered that the use of a link mechanism which keeps the inside rod ends at a constant pitch along the inner concave edge of a belt, both with dual pitch links and with nestable U-shaped outside links is particularly suitable for use in a conveying system wherein the belt travels along a helical path with the belt being arranged in a number of superimposed helically extending tiers.
Prior art helical tier systerns, such as disclosed in U.S. Patent Nos.
3,348,659 and 4,078,655 to Gerald C. Roinestad have used conveying belts with a collapsing inner edge. The successive tiers of belt in the '659 and ~655 patents are supported by a support frame separate from the belt. The minimum tier height in such a system is equal to the sum of the heights of the separate belt support frame, the ware being conveyed and the belt, resulting in a system with a relatively large vertical extent U.S. Patent No. 3,938,651 to Alfred et al. discloses a conveying system for conveying in a helical path wherein the belt is self-supporting along both the inner and outer edges of the belt.
Another aspect of the invention is directed to the construction of the U-shaped links, particularly the construction of the portion connecting the legs of the link. It has been known in the prior art to curve the bearing surface of the colmecting portion of U-shaped lin~cs.
For example, the bearing surface oî certain pintle chain links manu-factured by the Allied-Locke Industries, Incorporated are curved.
However, such prior art curved bearing surfaces for tractive links ~o not substantlally increase the wear characteristics of the links in the manner of the present invention.

The present invention is directecl to a conv~yor belt for con-veying around lateral curves. The lateral curves ha~/e a predeter-mined maximum curvature with a predetermined radius of curvature.
The belt is comprised of a plurality of rods and a mechanism for con-necting the rods to form a length of belt. The rods extend trans-versely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outsid~
edge of the lateral curves. The rods are arra~ged adjacent one another along the length of the belt. The connecting mechanism includes a link mechanism disposed adjacent the inside and outside ends of the rods for coupling adjacent pairs of rods to one another.
The link mechanism also keeps the inside and outside ends of the rods at substantially the same pitch during straight line motion of the belt.
During motion of the belt about a lateral curve, the link mechani~sm keeps the inside ends of the rods at the first pitch and allows the out-side ends of the rods to move to a second greater pitch as the belt moves from straight line to lateral curved motion and to return to the first pitch as the belt moves from the lateral curved to straight line motion. The link mechanism includes, along the inside concave edge of the belt, a plurality of separate inside links joining each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining each pair of adjacent rods. Each OI the out-side links has holes through which the rods extend including at least one slot to allow the outside ends of the rods to move to the second pitch. Each of the inside links includes holes having end surfaces spaced a predetermined distance such that a plurality of the inside links joining adjacent rods aligns the adjacent rods in a generally par-allel relation at the first pitch when the belt is under tractive load in straight line conveying motion.
In a preferred embodiment of the invention1 the inside links include at least two generally U-shaped links joining adjacent pairs of the rods, and the outside links include at least one link Joining adja-cent pairs of the rods. Each of the U-shaped links has a pair of spaced leg portions extending generally in the lengthwise dimension OI the belt and a connecting portion joining the spaced leg portions.
Each of the leg portions has holes forrned through lt for the pa~sage OI an adjacent pair of rods. The holes in the leg portions of the insicle links and in the outside links have end surfaces with predetermined longitudinal spacing between the end surfaces. The holes in the inside links have a first longitudinal end surface spacing, while the holes in the outside links have a second, greater longitudinal end surface spac-ing. The first longitudinal spacing is correlated to the second longitu~
dinal spacing and to the prede~ermined radius of c~rvature so that in straight line conveying motion the inside ends of t~e rods are kept at the first pitch and the inside U-shaped links are tractive while the outside links are non-tractive, and during lateral curved ~onveying motion the inside ends of the rods are kept at substantially the first pitch and at least one of the inside U-shaped links remains tractive while the outside ends of the rods move to the second greater pitch.
The correlation of the longitudinal spacing of the end sur~aces is preferably set so that the outside ends of the rods contact the opposing end surfaces of the holes in the outside links when the belt travels around a lateral curve of the pr~determined maximum curva-ture with the outside links assuming only a minimal amount of trac-tive load. Such a correlation assures that a~ least one of the inside links remains tractive and that the inside ends of the rods remain at substantially the first pitch. The use of this correlated spacing is particularly advantageous in a helical tiered conveying system wherein the curvature in the helix is the maximum curvature of the system. The belt can then be readily adapted to the system so that a non-collapsing inside edge is assured throughout the tiers of the sys-tem, while the outside edge of the belt moving through the tiers is stabilized by the contact of the rods with the end surface of the holes in the outside links.
Another embodiment of the link mechanism also holds the first and second transverse ends of the rods at substantially the same first pitch during straight line motion of the belt, ancl during motion of the belt about a lateral curvel this link mechanism holds the rocls to the first pitch along the transverse ends of the rods located at the irlside concave edge of the lateral curve. However, this link mechanism moves the opposite transverse ends o~ the rods to a second greater pitch along the outside convex edge of the lateral curve as the belt proceeds from straight line to lateral curved motion, and returns the opposite transverse ends of the rods to the first pitch as the belt moves from lateral curved to straight line motion.
The conveyor belt using the second embodiment of the link mechanism can be adapted to travel around lateral curves in a single direction or around lateral curves in both the right and left directions.
When the belt is designed to travel around lateral curves in a single - 6 -~

direction, the link mechanism includes both single pitch links and dual pitch links~ However, when the belt is designed to travel around lat-eral curves in both the left and right directions, dual pitch links are disposed along both edges of the belt. The dual pi~ch lin~s are pivotable between a first position and a second position. In the first position the transverse ends of the rocls connected by the respective links are held at the first pitch; and, during the pivoting motion of the links from the first to the second position, are moved from the first pitch to the second pitch.
Each of the dual pitch links includes a body which has a pivot aperture and a pitch changing slot. The transverse end of one of the rods is received in the pivot aperture and the transverse end of an adjacent one of the rods is slidably received in the pitch changing slot. A cam mechanism is provided for pivoting the dual pitch links between their first and second positions during motion around lateral curves.
A conveyor belt formed of the transverse rods and dual pitch links, or lin~s which allow the outside edge of the belt to expand while keeping the inside edge of the belt at a constant pitch, allows the belt to operate in a straight line direction and around curves without the problems resulting from a conveyor belt that has a collapsing inner edge as it proceeds around lateral curves.
~ nother preferred aspect of the present invention ls directed to the us~ of at least one support link joining pairs of the adJacent rods. The support linl~s include a longitudinal portion extending both longitudinally between a pair of the ad~acent rods and vertically away from the rods, and at least one tab portion extending transversely from the longitudinal portion. Holes are formed in each longitudinal portion to couple the support links to adjacent pairs of rods. The tab portions are spaced a predetermined vertical distance from the rod~s to contact an inside edge of an adjacent vertically spaced tier of the belt and thereby support the inside edge of the superimposed tlers when the belt is arranged to travel along a helical conveying path.
The present invention is also directed to a conveying system which uses belts of the type described and which move~s the belt through a helical conveying path that forms a plurality o~ stacked tiers of the belt. Belts which have a constant non-collapsing inside pitch are particularly useful in such stacked tier systems since a sig-nificantly less amount of belt is required for a given helical path over the amount of belt which is needed using prior art belts with a col-lapsing inside edge. Less amount of the belt is necessary to accommo-date the same amount of an offloading sur~ace. The use of a non-col-lapsing pitch in combination with a drive drum and support links along the inside edge of the belt is particularly advantageous, because local-ized shifting of the inside edge of the belt as it moves through the helical path is greatly minimized.
A further preferred aspect of the present invention is directed to the construction of the U-shaped links in a manner to substantially increase their wear characteristics. According to this aspect of the invention, tractive link members for connecting adjacent rods of an endless conveyor belt are comprised of a substantially flat piece of metal which is formed into a general U-shape with a pair of spaced leg portions joined by a connecting portion. The substantially flat piece of metal has a reduced thickness area in the connecting portion forrned of a compressed, wor~c-hardened area of the metal. The work-hardened area of the connecting portion forms a curved bearing sur-face against which a rod can bear.
In the system of the present invention the ware can be loaded as closely as possible, so that for a given ware capacity, the belt can be driven at a lower speed, thereby increasing the life of the belt, Also, the rod-link arrangement allows the belt to qe used in normal charge and discharge operations, and about end pulleys, rolls and take up mechanisms. Also, Ior a given inside radius of a lat0ral curve about which the belt travels, the tension on a belt of the present invention in a spiral or curved tier system would be less than with conventional rod-link belts.
The use of support links in accordance with the present inven-tion, wherein the support links are used in combination with constant pitch U-shaped inside links, also results in significant advantages.
The support links allow for a significant reduction in height of the .: .

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~ -- 8 -external belt support, while maintaining compatibility with sprockets and allowing the belt to proceed about comparatively tight bends around rolls, pulleys, etc.
Furthermore, these advantages are attained without the disadvantages of the collapsing inner belt edge mentioned above, such as lower efficiency, wrinkling o~ ware or freeziny together of adjacent ware. A smoother transition from straight line conveying into helical, stacked tier conveying also results from preventing the collapse of the inner edge of the belt by the constant pitch U-shaped inside links.
Finally, the use of tractive links having work-hardened bearing surfaces greatly enhances the wear characteristics of the tractive links. The work-hardened, curved inner bearing surface o~ the connecting portion of the links reduces wear elongation of the links in two ways.
First, by increasing the area of contact, the same volume of wear would represent a smaller elongation of the link pitch. Secondly, by forming the curved surface through a coining process which reduces the thickness o~ the connecting portion from a relatively large thickness to a smaller thickness, the connecting portion becomes work-hardened, wear resistant section of material. Prevention o~ wear elonyation o~ tractive links is particularly important for the belt of the present invention wherein the belt and conveyor systen are designed so that the inside links remain tractive in both straight line and lateral curved motion, and, as the belt is ~requently used in environments where sanitation is important, undesirable wear debris can be diminished.
Other aspects of this invention are as follows:
A conveyor belt for conveying in both a straight line direction and around lateral curves in a single - a direction, the lateral curves having a predetermined maximum curvature with a predetermined radius of curvature, the conveyor belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge o~
the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length o~ the belt, said connecting means including link means disposed adjacent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means keeping the inside and outside ends o~ said rods at substantially the same first pitch during straight line motion of said belt and said link means further, during motion of the belt about said lateral curves, keeping said inside ends of said rods at substantially said first pitch and allowing said outside ends of said rods to move to a second greater pitch as the belt moves from straight line to lateral curved motion and to return to said first pitch as the belt moves from lateral curved to straight line motion, said link means including, along the inside concave edge of the belt, a plurality of separate inside links joining each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining each pair o~ adjacent rods, each of said outside links having holes thxough which said rods extend including at least one slot to allow the outside ends of said rods to move between the first and second pitches, each of said inside links including holes having end sur~aces spaced a predetermined distance such that a plurality of said inside links joining adjacent rods aligns the adjacent rods in a generally parallel relationship at said first pitch when said belt is placed under tractive load in straight line conveylng motlon.
A conveyor belt for conveying in both a straight line direction and around lateral curves in a single .: ~, ~!

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- 8b -direction, the lateral curves having a predetermined maximum curvature with a predetermined radius of curvature, the conveyor belt comprising a plurality of rods and connecting means for connecting said rods to for~ a length of the belt, said rods extending transvPrsely of the length of the belt between an inside end along the inside edge o~
the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adjacent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said links means including, along the inside concave edge of the belt, at least two generally U-shaped inside links joining the inside ends of each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining the outside ends of each pair of adjacent rods, said generally U-shaped inside links each having a pair of spaced leg portions joined by a connecting porkion, each of said leg portions having holes for receiving said rods, each of said outside links having holes for receiving said rods, said holes in the legs of said insi.de links having end surfaces with a first predetermined longitudinal spacing, said holes in said outside links having end surfaces with a second predetermined longitudinal spacing, said first and second longitudinal spacings; being cvr-related to one another and to the predetermined radius of curvatu~e so that in straight line conveying motion the inside ends of said rods are kept at a irst pitch and the U-shaped inside links are tractive while the outside links are non-tractive, and during lateral cuxved conveying motion the inside ends of said rods are kept at substan~
tially the first pitch and at least one of said U-shaped inside links remains tractive while the outside ends of said rods move to a second greater pitch.

~b -8c-A conveyor belt for conveying in both a straight line direction and around lateral curves in a single direction, the latsral curves including a helical path and having a predetermined maximum curvature with a predetermined radius of curvature in the helical pakh, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adjacent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means including at least two generally U-shaped inside links and a support link disposed along the inside edge of said belt, and at least one outside link disposed along the outside edge of the belt, said inside U-shaped links each hav.ing a pair of spaced leg portions connected by a connecting portion, each of said leg portions having holes for receiving adjacent ones of said rods, each of said outside links having holes for receiving adjacent ones of said rods, said support links having a longitudinal portion extending both lonyitud.inally between a pair of said adjacent rods and vertically away from said rods and at least one tab portion extending transversely from said longitudinal portion, said tab portion being spaced a predetermined vertical distance from said rods to contact and support an inside edge of an adjacent vertically spaced tier of said belt when said belt travels along the helical path, said longitudinal portion of said support links having holes for receiving adjacent ones of said rods, said holes formed in said inside links having end surfaces with a first predeterm.ined longitudinal spacing, said holes l3~
~ 8d -formed in said outside links having a second predetermined longitudinal spacing, said first and second longitudinal spacings being correlated to one another and to the pre-determined radius o~ curvature such that in straight line conveying motion the inside ends o~ said rods are kept at a first pitch and the inside U-shaped links are tractive while the outside links are non-tractive, and during lateral curved conveying motion the inside ends of said rods are kept at substantially the first pitch and at least one of the inside U-shaped links remains tractive while the outside ends of the rods move to a second greater pitch.
A tractive link member for connecting adjacent rods of an endless conveyor belt and for assuming tractive load, the links comprising a substantially flat piece of metal formed into a general U-shape with a pair of spaced leg portions ~oined by a connecting portion, each of said leg portions having at least one hole for receiving adjacent rods of a conveyor belt, said substantially ~lat piece of metal along the length of said connecting portion having both a first thickness area and a second, reduced thickness area, said reduced thickness area being a compressed work-hardened area of said metal, said reduced thickness arPa in said connecting portion ~orming a curved bearing sur~ace against which a rod can bear.
In a conveyor system including a conveyor belt and a drive means for moving the belt along a conveying path, said system orienting the belt in both a s~raight line direction and around lateral curves in a single direckion, the lateral curves including a helical portion ~orming a plurality of stacked tiers of the belt and having a pre-determined maximum curvature with a pxedetermined radius of curvature in the helical portion, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending - 8e -transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinal-ly along the length of the belt, said connecting means including link means disposed ad~acent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means keeping the inside and outside ends of said rods at substantially the same first pitch during straight line motion of said belt and said link means further, during motion of the belt about lateral curves keeping said inside ends of said rods at said first pitch and allowing said outside ends of said rods to move to a second greater pitch as the belt moves from straight line to lateral curved motion and to return to said first pitch as the belt moves from lateral curved to straight line motion, said link means including, along the inside concave edge of the belt, a plurality o~
separate inside links joining each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining each pair o~ adjacent rods, each o~ said oukside links having holes through which said rods extend including at least one slot to allow the outside ends of said rods to move between the first and second pitches, each of said inside links including holes having end surfaces spaced a predetermined distance such that a plurality o~ said inside links joining adjacent rods aligns the adjacent rods in a generally parallel relationship at said first pitch when said belt is placed under tractive load in straight line conveying motion.
In a conveying system including a conveyor belt and a drive means for moving the belt along a conveying path, said system orientating the belt in both a straight line direction and around lateral curves in a single direction, the lateral curves including a helical portion ~orming a - 8f -plurality of stacked tiers of the belt, and having a predetermined maximum curvature with a predetermined radius of curvature in the helical portion, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinal-ly along the length of the belt, said connecting means including link means disposed adjacent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means including, along the inside concave edge of the belt, at least two generally U-shaped inside links joining the inside ends of each pair of adjacent rods, and, along the outside edge of the belt at least one link joining the outside ends of each pa.ir of adjacent rods, said generally U-shaped inside links each having a pair of spaced leg portions joined by a connecting portion, each of said leg portions having holes ~or receiving said rods, each o~ said outside links having holes for receiving said rods, said holes in the legs of said inside linlcs having end surfaces with a first pre-determined longitudinal spacing, said holes in said outside links having end surfaces with a second predetermined longitudinal spaciny, said f1rst and second longitudinal spac.tngs being correlated to one another and to the predetermined radius of curvature 50 that in straight line conveying motion the inside ends of said rods are kept at a first pitch and the U-shaped inside links are tractive while the outside links are non-tractive, and during lateral curved conveying motion the inside ends of said rods are kept at substantially the first pitch and at least one of the U-shaped inside links remains tractive while the outside ends of said rods move to a second "~
., .~, - 8g -greater pitch.
A conveyor belt for conveying in both a straight line direction and around lateral curves comprising: a plurality of rods extending transversely of the length o~
the belt, having firsk and second transverse ends, said rods arranged adjacent one another longitudinally along the length of the belt; and means for connecting said rods to form a length of the belt including link means, disposed approximately adjacent said first and second transverse ends of said rods for coupling adjacent pairs of each of said rods to one another, for holding the first and second transverse ends of each of said rods at a substantially same first pitch during straight line motion of said belt, for holding the transverse ends of each of said rods located at the inside concave edge of a lateral curve to the first pitch during motion of the belt about the lateral curve, for moving the opposite transverse ends of each of said rods to a second greater pitch along the outside convex edge of the lateral curve as the belt moves from straight line to lateral curved motion, and for returning the opposite transverse ends of each of said rods to the first pitch as the belt moves from lateral curved to straight line motion.
A conveyiny system comprising: means for moving a conveyor belt in a straight line direction and around lateral curves in at least one direction; ~ conveyor belt including: a plurality of rods extending transversely o~
the length of the belt, each rod having ~irst and æecond transverse ends, said rods arranged adjace~t one another longitudinally along the lengkh of the belt; and a plurality of links connecting said rods to form the length of belt, said links disposed approximately ad}acent said first and second transverse ends of said r.ods for coupling ad~acent pairs of said rods to one another, said links ., ij~.~
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holding the ~irst and second transverse ends of said rods at a substantially same first pitch during straight line motion of said belt, and during motion of the belt about a lateral curve holding the transverse ends of said rods located at the inside edge of the lateral curve to the first pitch, moving the opposite transverse ends of said rods to a second greater pitch along the outside edge of the lateral curve as the belt moves from straight line to lateral curved motion and returning the opposite transverse ends of said rods to the first pitch as the belt moves from lateral curved to straight line motion, said links including dual pitch links disposed approximately along at least one transverse edge of said belt, each of said dual pitch links including a body having a pivot aperture and a pitch changing slot, the transverse end of one of said rods received in said pivot aperture and the transverse end of an adjacent one of said rods being slidably received in said pitch changing slot, said pitch changing slot having a first pitch area where the transverse end of said adjacent one of said rods is received when the rods are spaced by said first pitch and a second pitch area where the trans-verse end of said adjacent one of said rods is received when the rods are spaced by said second pitch; and means for pivoting said dual pitch links between their fi~st and second positions when said belt is driven past said pivoting means.
A conveyor belt including a plurality of rods extending transversely of the length of the belt between inside and outside edges of the belt, a pl~rality of first links disposed adjacent inside ends of said rods, and a plurality of second links disposed adjacent outside ends of said rods, the improvement comprising: each of said first links coupling adjacent rods to each other.near the inside edge of said belt; each of said second links coupling adjacent rods to each other near the outside edge of said ~3~

- 8i belt; and said belt construGted for holding said inside ends of said rods at a first pitch relative to each other during straiyht-line travel of said belt, for holding said inside ends of said rods at said first pitch relative to each other during curved travel of said belt and for allowing said outside ends of said rod to move to a second greater pitch relative to each other during said curved travel of said belt.
Further objects, features and other aspects of this invention will be understood from the following detailed description of the preferred embodiment of this invention referring to the annexed drawings.

BRIEF DESCRIPTION OF THE_DRAWINGS
Figure 1 is a plan view of a portion of a conveyor belt in accordance with the present invention, illustrating the belt traveling in a straight line direction;
Figure 2 is a plan view of the conveyor belt of Figure 1, illustrating the belt passing around a lateral curve:

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Figure 3 is a sectional view taken generally along lines 3-3 o~
Figure l;
Figure 4 is a sectional view taken generally along line 4-4 of Figure l;
Figure S is a plan view of an improved U-shaped link having a work-hardened, curved bearing surface and modified leg portions;
Figure 6 is a side view of the link illustrated in Figure S;
Figure ~ is a schematic plan view of a portion of a conveyor belt in accordance with the present invention, using a second embodi-ment of a link mechanLsm and illustrating the belt passing around a lateral curve;
Figure ~ is a schematic plan view of the conveyor belt of Figure 7, illustrating the belt traveling in a straight line direction;
Figure 9 is side view of a dual pitch link in accordance with the present invention;
Figure 10 is a sectional view taken generally along the line 10-10 of Figure 9;
Figure 11 is a sectional view taken generally along the line 11-11 OI Figure 9;
Figure 12 is a schematic side view, illustrating another embodi-ment of dual pitch links pivoting from a first pitch to a second greater pitch:
Figure 13 is a schematic side view similar to E'igure 12, illUS-trating the dual pitch links pivoting :~orm the second greater pitch to the first shorter pitch;
Figure 1~ is an end view, partlally in section, illustrating a guide track ~or receiving a rod end;
Figure 15 ls a schematic top plan view illu.strating a conveyor belt designed to travel in both lateral directions With dual pitch links on b~th transverse edges of the bel~;
Figure 16 i5 a side view of a support link in accordance with the present invention;
Figure 17 is a front edge view of the support link illustrated in Figure 16;

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Figure 18 is a top plan view of the support link illustrated in Fig. 16;
Figure 19 is a schematic vertical sectiorlal vlew illustrating a pair o~ stacked tiers of a conveyor belt with the support links disposed along the inside edge of the belt:
Figure 20 is a top plan view of a portion of the conveyor belt illustrated in Figure 19;
Figure 21 is a side view along the inside trans-verse edge of the conveyor belt illustrated in Figure 19;
Figure 22 is a schematic drawing of a conveyor system in accordance with the present invention wherein the belt conveys about a helical path and is driven by a frictional drive mechanism; and Figure 23 is a schematic drawing of another embodiment of a conveyor system in accordance with the present invention wherein the conveyor belt conveys about a helical path and i5 driven by a positive belt mechanism.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the Figures wherein like numerals indicate like elements, a portion of a conveyor belt 10 is shown in Figures 1 and 2. Figure 1 illustrates the orientation of belt 10 as it moves in a straight line conveying motion, and Figure 2 illustrates the orientation of belt 10 as it moves in a lateral curved direction to the left. The left edge of belt 10 therefore can be described as the inside concave edge o~ belt 10, while the right edge can be described as the outside convex edge of belt 10.
Conveyor belt 10 is formed oE a plurality of rods 12, which extend transversely of the length o~ belt 10 between inside and outside ends, inside links 14 and 15 along the inside edge of belt 10 and outside links 16 and 17 along the opposite, outside edge of belt 10. Links 14, 16 and 17 couple adjacent rods 12 to one another to form a length of belt 10. A woven mesh material 18 may be disposed around ,~S ~1 ~6~

rods 12 and between links 14 and 16. The ends of rods 12 have enlarged or upset ends. Insidemosk links 14 are held in position by welding to the inside enlarged ends of rod 12. The outermost inside links 15 and outside links 16 are likewise held in transverse position by being welded to rods 12.
Links 14 and 15 are generally U-shaped links having leg portions 20 which extend generally in the lengthwise direction of belt 10, and connecting portions 22, which join leg portions 20. Leg portions 20 have a pair of spaced holes 24, 25 for receiving the inside ends of a pair of rods 12. Holes 24, at the trailing end of links 14 and 15, are slightly oversized with respect to the cross-sectional dimension of rod 12 to permit cleaning of the belt. Holes 25, at the leading end of links 14 and 15, are in the form of a slot of oversized width, l.ikewise for the purpose of permitting cleaning. Holes 24 and 25 are located and shaped so that the inside ends of rods 12 are kept at a first pitch (center to centPr spaciny between adjacent rods 12) when the belt is under tractive load~
Also, links 14 and 15 and rods 12 along the inside concave edge of belt 10 remain under tractive load during both straight line motion and lateral curved motion. As will be explained, the inside portions of rods 12 are kept at the first pitch and under tractive load in both straight line motion and lateral curved motion of belt lD by the speci~ic design o~ the combination o~ links 14, 15, .16 and 17, which form a link mechanism ~or belt 10.
Inside links 14 and 15 have leg portions 20 which are substantially straight and which diverge outwardly from opposite ends of connecting portion 22. Alternatively, the inside links can be configured as links 14 t ~ which are generally U-shaped and are illustrated in.Figures 5 and 6.
Link 14' has a connecting portion 22' similar to connecting portion 22, however, leg portion 20' are formed different ~2~

from leg portions 20. Each leg portion 20' includes an inner section 42 extending generally perpendicular from connecting portion 22', a middle section 44 diverging outwardly from inner section 42, and an outer section 46 extending from middle section 44 in a direction generally parallel to inner section 42.
Outside links 16 likewise each have a pair of spaced apart leg portions 28 joined by a connecting portion 30. Leg portions 28, like leg portion 20', include inner and outer sections 29 and 31, orientated perpendicular to connecting portion 30, which are joined by a middle out-wardly diverging section 33 so that leg portions 28 take on a stepped configuration, gradually increasing in width away from connecting portion 30. Such a configuration is similar to prior art nestable U-shaped links. As seen in Figure 3, each leg portion 28 has a pair of holes 34, 35 for receiving adjacent rods 12. Hole 35, which is adjacent connecting portion 30 is in the form of an ~longate slot, which allows rods 12 to move from the collapsed position shown in Figure 1 during straight line conveying motion, to the expanded position shown in Figure 2, during conveying about lateral curves.
In addition to U-shaped links 16, bar links 17 can be disposed in a single row along the outer transverse edge of belt 10 between outside links 16 and the enlarged heads at the outer ends o~ rods 12. Similar to }inks 16, links 17 have a pair o~ holes, a~ least one o~ which is slot~ed to permit the expansion of the pitch of the outer edge of belt 12.
Each link 14, 14' i5 formed of a substantially 1at piece of metal. The flat piece of metal has a first thickness Tl along the top and bottom areas of connecting portions 22, 22' and along leg portions 20, 20'. A curved bearing surface 126, 126' is formed in the inner surface of connecting portions 22, 22', while the outer surface ~ ~ I
., . ~ ,, remains substantially flat. Bearing sur~ace 126, 126' is formed by a coining process wherein the material of connecting portions 22, 22' is compressed to a maximum reduced thickness T2. The compressed, reduced thickness area thus becomes a work-hardened area of connecting portions 22, 22'. The maximum reduced thickness T2 is at least 90% of thickness Tl and not less than preferably 70%, with a typical example being Tl of 0.105 inch reduced to T2 of 0.80 inch. The curved bearing surface substantially mates with the outer surface of rod 12, i.e. has substan-tially the same radius of curvature. Links lS can also include a work-harden~d bearing surface. However, this is not necessary since links 16 are designed not to take on any significant tractive load.
Conveyor belt 10 and links 14, 15, 16 and 17 are designed to be used in a conveying system wherein belt 10 will travel about lateral curves in a single direction and the lateral curves have a predetermined maximum curvature, i.e., the radius of curvature of the tightest lateral curve in the system will not be below a predetermined value.
Links 14, 15, 16 and 17 will have predetermined spacing between the forwardmost and rearwardmost surfaces of the holes in the links which is correlated to the predetermined maximum curvature of the belt travel and to one another.
This correlation o~ spacing is set to assure that the portions o~ rods 12 alony the inside edge o~ the belt remain at substantially the first pitch, and that at least one o~ the inside links 14, 14~ continues to bear a tractive load while the belt proceeds around lakeral curves up to the predetermined maximum curvature.
Conveyor belt 10 is driven along its inside edge in a conventional manner by a drive sprocket or drive cage engaging the inside edge of the belt. As the belt travels in a straight line direction, the tractive load is shared by all the inside links, and the inside ends of the rods are kept at the first pitch. The use of at least two inside U-shaped links assures that rods 12 extend substan-tially parallel during straight line motion under tractive load. If only one U-shaped link were used along the inside edge, the rods might extend in a non-parallel manner due to inaccuracies in the formation of the U-shape. It is there-fore important that a plurality of inside links be used to assure the parallel alignment of the rods.
As belt 10 travels about a lateral curve, the outside ends of rods 12 expand in the slots of the outside links 16, 17 and the tractive load gradually shifts to the inside links farthest from the inside edge of the belt.
Links 14 and 15 have a first predetermined spacing between the forwardmost and rearwardmost surfaces of their holes, and outside links 16 and 17 have a s~cond, greater spacing between the forwardmost and rearwardmost surfaces of their holes. The first and second predetermined spacings are correlated to one another and to the predetermined maximum curvature of the belt so that outside links 16 and 17 assume only a minimal amount of the tractive load during travel about a lateral curve of the predetermined maximum curvature. Preferably, this predetermined spacing results in rods 12 contacting the bearing surfaces of the holes in outside links 16 and/or 17 without assuming any measurable tractive load so that inside links 14 and 15 continue to assume substantially all the tractive loadl This condition is particularly desirable because links 16 and 17 will allow only a negligible amount of play between links 16, 17 and the bearing surface~ ot rods 12, thereby assuriny smoothness of operation, while also insuring that the inside links remain tractive and the inside edge of the belt does not collapse. This is accomplished by setting the ratio of the spacing (PO') of the holes in the outside links 16, 17 to the distance (Ro) from the center of the radius of curvature of the bel~ ~o the outermost outside - 14a -links in the tightest curve over slightly greater than the ratio of the spacing (Pi) of the holes 24, 25 in the inside links 14 and 15 to the distance (Ri) from the center of the radius of curvature of the belt to the outermost leg 20 of inside links 14 and 15. Using the equation:
Ro x Pi = Po; then Ri PO~ = PO + 0.005 to 0.010 inches. For example, in a system with a four and a half (4 1/2) foot radius drive cage, two one-inch inside links, and a three (3) foot wide belt: Ri =
56 inches; Ro = 90 inches; Pi = 1.080 inches; and PO =
1.735 inches; then PO' = 1.740 to 1.745 inches. In such a belt, where the tractive load in the helical path could typically be 200 pounds, the inside links would continue to assume 150 to 200 pounds o~ the tractive load in lateral curves of the predetermined maximum curvature.
In addition, U~shaped outside links 16 serve an important function in preventing the outer edge of belt 10 from lagging an unacceptable amount behind the perfect radial extension of rod 12 from inner links 14 and 15.
Such lagging is a result of a drag force created by the weight of belt 10 and its associated product load on a support surface as the belt moves about a lateral curve.
In order for the rods to lag, links 16 would ha~e to rotate with respect to a perfect radia:l line of the rods in a curved path; however, such rotation is held to a minimum by the nesting action of consecutive U-shaped outside links 16, thereby restricting the amount of lag ~hat can occur.
For manufacturing ease, when U-shaped links 16 are used in combination with bar links 17, bar links 17 can be designed to have the correlated spacing PO~ and links 16 can have an even greater longi~udinal spacing between the end surfaces of their holes, thereby functioning principally to prevent lag.
" ~

, ~ . .

'7~
- 15 ~
Referring to the Figures 7 15, a second embodiment of a conveyor belt, designated generally lOa is illustrated. A portion of a conveyor belt lOa is shown in Figures 7 and 8. Conveyor belt lOa is formed o~ a plurality o~ rods 12a, single pitch links 14a and 15a along one edge o~ belt lo and dual pitch links 16a along the opposite edge of belt lo. Rods 12a extend transversely of the length of belt lOa and they have enlarged or upset ends. Links 14a, 15a and 16a couple adjacent rods 12a to one another to form a length of belt lOa.
Single pitch links 14a can be conventional U-shaped links having apertures for receiving the inside ends of a pair of rods 12. The apertures in links 14a and 15a are slightly oversized with respect to the cross-sectional dimension of rods 12a to permit cleaning, nevertheless, links 14a and 15a hold the ends of rods 12a to substantial-ly a constant or single pitch. Alternatively links 14a and 15a can be formed with work-hardened bearing surface as in links 14 and 14' or can take on the configuration of links 14'.
Links 16a are dual pitch links designed to change the pitch of rods 12a (spacing between adjacent rods 12a) along the edge at which they are disposed between a first pitch and a second greater pitch. The ~irst pitch i5 sub-stantially equal to the pitch at which links 14a and 15a hold the inside ends of rods 12a during straight line motion as shown in Figure 8. When belt 10~ proceeds around a lateral curve, as shown in F'igure 7, dual pitch links 16a move the outside ends o~ the rods to which they are coupled to the second greater pitch along the outside convex edge o~ the lateral curve, while links 14a and 15a hold the inside ends of the rods to which they are attached to the first pitch along the inside concave edge ~of the lateral curve. As with rods 12, the inside portions of rods 12a are kept at substantially the first pitch and under tractive loacl in both straight line motion and lateral curved motion of belt lOa by the specific design of the combination of single pitch links 14a and 15a and dual pitch links 16a, which form a link mechanism for belt lOa.
Figure 9 illustrates the structural details of one embodiment o~ a dual pitch l:ine 16a. Link 16a is preferably formed as a single integral body 180 which has a generally triangular shape or perimeter. A pivot aperture 200 and an elongate pitch changing slot 220 are formed through body 180 of dual pitch links 16a. As further illustrated in Figures 10 and 11, body 180 can be formed of two thicknesses of materialr i.e., a thick portion 240 extending around a substantial portion of aperture 200 and slot 220, and a thinner web portion 260 filling in and extending around the border of thicker portion 240. A two thickness configuration of body 180 is particularly suitable for a body 180 formed of a molded plastic material wherein a sturdy border is provided for aperture 200 and slot 220, while the thinner web portions 260 form an easy to handle, structurally sound and material saving configuration for the integral body 180.
Figures 12 and 13 illustrate an alternate, simplified configuration for the body of dual pitch links 16a, identi~ied as body 1~0'. As seen therein, body 180' is formed of a flat piece of material containing aperture 200 and slot 220. The shape of body 18U' is particularly suitable for links 16a made from machined metal.
Referring to Figures 7, 8, 12 and 13, operation of belt lOa will be explained. Figure 8 illustrates belt lOa proceeding in a straight line direction indicated by arrow A. As seen therein, the pitch is the same at both edges of belt lOa. Links 14a and 15a are single pitch links which hold adjacent rods at this constant pitch. The position of adjacent rods in straight line conveying is illustrated in ;'~, 7~

Figure 12 by the left-most pair of rods 12a, and the three right-most rods in Figure 13. Referring to Figure 12, a first rod 12a is received in pivot aperture 200 of the left-most dual pitch link 16a and an adjacent rod 12a is received in pitch changing slot 220 of this link 16a.
The last-mentioned rod 12a is located in a firs~ pitch area 280 of slot 220 which is located adjacent rods 12a at substantially the same pitch as links 14a and 15a locate the adjacent rods. This pitch is the shortest pitch allowed by line 16a. In this condition, tractive load can be shared between the U-shaped single pitch links 14a and 15a and the dual pitch links 16a. Links 14a, 15a and 16a can be dimensioned, however, so that the relative amounts of tractive load can be shared unevenly. For example, when dual pitch links 16a are formed of a plastic material, it is desirable to have single pitch links 14a and 15a, which are generally formed of metal, carry more of the tractive load.
The orientation of rods 12a, when belt lOa proceeds around a lateral curve, as shown by arrow B, is illustrated in Figure 7. As seen therein, the inside concave edge of belt lOa remains at the same ~irst pitch a~ in stralght line motion, while the outside convex edge of belt lOa has been moved to a greater pitch by dual pitch links 16a.
Figure 12 illustrates the pivoting motion of links 16a that moves the outside ends o~ rods 12a along the outside edge to the second greater pitch. As seen therein, a cam surface or the like 340 for pivoting the dual pitch links is located adjacent outside edge of belt lOa in alignment with links 16a. As belt lOa proceeds in the direction of arrow C, an upper edge of links 16a contacts cam surface 340 which causes links 16a to pivot in a counterclockwise direction. The pivoting motion of links 16a causes the ends of rods 12a received in the pitch changing slot 220 to slide from the first pitch area 280, wherein adjacent rods ,.
'~b , 7~L

12a are close to one another, to a second pitch area 360 where the spacing between adjacent rods 12a is greater.
The pitch changing slot second pitch area forwardmost end surface is 370. See also, Figure 9. As seen in Figure 12, cam surface 340 can cause link 16a to pivot 90 and locate rod 12a carried in slot 220 at the furthest end of slot 220 to contact the second pitch area 360 end sur~ace 370. The length and orientation of pitch changing slot 220 is selected to accommodate the greatest pitch along outside curve edge for a given system. Of course, if smaller pitches are required within the same system, cam surface 340 can be designed to pivot dual pitch links 16a to a lesser degree, thereby locating the end of rod 12a recei.ved in slot 220 within an intermediate positio~ in second pitch area 360.
Figure 13 illustrates the manner in which links 16a are pivoted to return rods 12a from the second pitch used in lateral curved motion to the first pitch used in straight line conveying. As shown therein, belt lOa proceeds in the direction of arrow D and links 16a contact a cam surface or the like 380, which pivots links 16a in a clockwise direction. The clockwise pivoting motion of links 16a moves the ends of transverse rods 12a from the second pitch area 360 to the first pitch area 280 of pitch changing slots 220.
As seen in Figure 1.4, an elongate ~uide hlock 400, havi.ng a guide slot 420, can be located adjacent the belt outer edge in the transition area where cam surfaces 340 and 380 cause pivoting motion of links 16a~ The outermost ends of rods 12a are carried within guide slot ~20 to keep the end of rods 12a within the plane of conveying motion of belt lOa during pivoting of links 16a. As further seen in Figure 14, the ends of rods 12a received within slot 420 preferably have a double struck upset head, which assures that the end of transverse rod 12a remains within guide -slot 420 even after wear occurs. Guide slot 420 can be eliminated at curves where smooth travel of the belt is not required, for example, on return portions of the conveyor where no ware is being transported, or on a loaded portion of the conveyor if a slight momentary humping of the conveyor surface will not disarrange the ware.
Similar to conveyor belt 10 and links 14, 15, 16 and 17, conveyor belt lOa and links 14a, 15a and 16a can be used in a conveying system embodiment wherein belt lOa will travel about lateral curves in a single direction and the lateral curves have a predetermined maximum curvature, i.e., the radius of curvature of the tightest lateral curve in the system will not be below a predetermined value.
Single pitch links 14a and 15a and dual pitch links 16a will have predetermined spacing between the forwardmost and rearwardmost surfaces of the holes or slots in the links which are correlated to the predetermined maximum curvature of the belt travel and to one another. This correlation of spacing is set to assure that the portions of rods 12a along the inside edge of the belt remain at substantially the first pitch, and that at least one of the inside single pitch links continues to bear a tractivP load while the belt proceeds around lateral curves up to the predetermined maximum curvature. This correlation of spacing is set in the same manner as discussed above with respect to belt 10.
Conveyor belt lOa, also similar to conveyor belt 10, is driv~n alony its inside edge in a conventional manner by a drive sprocket or drive cage engaging the inside edge of the belt. As the belt travels in a straigth line direction, the tractive loa~ is normally shared by all the single pitch links 14a and 15a, and the inside ends of the rods are kept at the first pitch~ The use of at least two inside U-shaped links helps assure that rod~ 12a extend substantially parallel during straight line motion under tractive load.

As belt lOa travels about a lateral curve, the outside ends of rods 12a expand in the pitch changing slot5 220 of the dual pitch links 16a. The rod actually expands from the slot first pitch area 280 to the second pitch area 360. Also, the tractive load gradually shi~ts to one o~
the two single pitch links which is farthest from the inside edge of the belk.
Figure 15 illustrates an embodiment of belt lOa wherein a conveyor system uses dual pitch links 16a disposed along both sides of the belt in order to allow the belt to travel in both the left and right directionsas shown by arrows E and F. In such motion, the dual pitch links on the inside edge of the curve would remain at the first pitch position, while dual pitch linXs 16a along the oustide edge of the curve would be pivoted to the second, greater pitch orientation. Figure 15 also illustrates belt lOa as part of a conveying system with a conventional conveyor drive mechanism 460, such as a sprocket drive, for moving the conveyor belt 12a.
A mesh overlay 480 placed around rods 12a is also illustrated in Figure 15. Mesh overlay 480 can be of any conventional design, such as wire formed into ~lattened helicals. The overlay is used to provide support for relatively easily damaged ware. The overlay can be manu-factured to a width somewhat wider than its final assembled ~orm on belt lOa so that it providas pressure in the transverse direction against both the inner and outer links to assure that they maintain their transverse position on rods 12a, thereby eliminating the need ~or ~urther welding or the use of mechanical devices to hold th~ links in place~
Figures 19, 20, and 21 illustrate an embodiment o~
the invention wherein a conveyor belt 10' is used in a conveying system in which belt 10' travels along a helical 6'7~
~ 21 ~
path comprised of a number o~ superimposed helically extending tiers. The conveyor belk of this embodiment will be designated 10', with elements of belt 10' which are similar to belt 10 indicated by like primed numerals.
Figures 16, 17 and 18 illustrated details of an inside support link 40 used with belt 10'.
Support links 40 include a longitudinal portion 48 and tab portions 50. Lonyitudinal portion 48 is formed in two sections, i.e., a lower section 49 and an upper section 51. Lower section 49 contains a pair of holes 55 for receiving ends of adjacent rods 12', and tab portions 50 extend in opposite transverse directions from an upper end of upper section 51. Upper section 51 extends both upward and longitudinally in two directions from lower section 49.
As best seen in Figure 21, a first support link 40A is coupled to a first pair of adjacent rods 12A', while the next support link 40B is coupled to the next separate pair of adjacent rods 12B'. Lower section 49 is held in align-ment with the direction of travel of belt 10' by end sections 46 of U-shaped links 14'. Upper section 51 of support links 40 are angularly offset by approximately 4 degrees from the respective lower sections 49 in order to allow the lonyitudinal ends of adjacent longitudinal portions 51 to overlap. One end of longitudinal portions 51 include dimples 53 which keep the overlapping portions of adjacent support links 40 out of contact to permit c]eaning. As seen in Figure 16, upper portion 51 includes slot 56 disposed between tab portions 50.
Each tab portion 50 has a width which is sufficient to contact and support links 14' and 15' disposed in a tier above it. Also, the length of each tab portion 50 is set so that the belt 10' can proceed around reverse bends without adjacent tab portions 50 coming into contact with one another.

7~
As seen in Figure 19, as the belk proceeds around a helical path, the outer ends of belt 10 are supp~rted by an independent support structure 60. Support structure 60 includes a plurality of vertical members 62 (one of which i5 illustrated), from which a plurality of horizontal tier supports 64 extend. Each tier support 64 includes a low friction bearing material 66 on which outer links 16' slide. The inside edge o~ belt 10' is supported on a rotating base (not shown) and successive tiers of the helical path created by belt 10' are supported one upon another by means of support links 40. To accomplish this self-supporting feature, the vertical distance which tab portions 50 are located above rods 12' is selected to accommodate the particular helical path and the ware to be supported on belt 10'. Belt 10' is driven by an internal rotating cage which includes a plurality of vertically extending driving members 70. Figure 19 illustrates belt 10' with generally U-shaped outside link 16' and bar links 17'. However, belt 10' can also incorporate dual pitch links 16a along the outside edge of belt 10'.
Re~erring now to Figure 22 a spiral low tension helical tier conveyiny system 100 of the type shown in U. S. Patent Nos. 4,078,655 and 3,348,659 is illustrated.
System lO0 can incorporate either of the belts 10, 10' or lOa o~ the present invention. Since the 1QW tension is ~ully described in these patents, and such helical conveying systems are known in the art only a brief description will be given here. In such a low tension system 100, a cage type driving drum 102 frictionally engages the inner edge of belt 10 (10', lOa) to drive it with relatively low tension through a helical path around the drum. In addition, a positive sprocket drive 104 engages the belt lO along a straight portion thereo~. A
motor 105 drives the drum 102 through gearing 106 and also drives the positive sprocket drive 104 through ,-~
, ,~

.

~ 22a -interconnected yeariny 107. The belt lO travels from the sprocket drive 104, past weighted tension take up roller 110 and idler pulleys 111 to a straight loading portion 108, then in helical loops 112 around the drum 102 to a straight discharge portion 109 and around another ider 111 back to drive sprockets.
Referring now to Figure 23 a sprial very low tension helical tier conveying systems 200 of the type shown in U. S. Patent No. 4,741,430, issued on May 3, 1988 to Gerard C. Roinestad is illustrated. System 201 can incorporate either of the belts 10, 10' or lOa of the present invention. Since the very low tension system is fully described in that patent application, and such helical conveying systems are known in the art only a brief description will be given here. In such a system 201, a cage type driving drum 202 positively engages the inner edge of belt 10 (lG', lOa) to drive it with very low tension through a helical path around the drum. Driving drum 202 functions as the primary drive for the belt moving in the helical path; however, secondary drives 204 and 206 are provided adjacent the inlet and outlet of the helical path to maintain a desired fixed length of the belt in the helical path.
Belts lO and 10' are particularly suited for use in helical tier systems 100 and 201. The maxlmum curvature o~
the system is located in the helical path and the spacing between the openings in links 14, 15, 16, 17 (and 40, if used), or between 14a, 15a and 16a, is correlated to the radius of curvature of the helical path. This assures non-collapse of the inner edge of the belt within the helical path, while at the same time assuring smooth operation of the belt along its outer edge.
As seen in Figure 22, a helical conveying system includes an endless conveyor belt lO (lO', lOa), having a ~36~i~7~L
~ 22b straight-]ine loading section 108, a helical path sectio~
112 and a straight-line discharge section 109. As s~en in Figures 1 and 2, the belt has a plurality of transverse rods 12 extending from an inner lateral edge to an outer lateral edge of the belt. Rods 12 are interconnected by innermost inside links 14 near the ends khereof adjacent the inner lateral edge in a helical path section 112.
Interconnections between links 16 and 17 and rods 12 alony the outer edge of the belt 10 of Figures 1 and 2 permit relative expansive longitudinal movement of an amount sufficient to accommodate the increase in distance whi~h occurs during the transition of the belt from its straight-line loading section 108 configuration to a curved con~igu-ration having a desired radius of curvature for the helical path section 112. As seen in Figures 1 and 2, the belt also includes outermost inside or third links 15 inter-connected to adjacent transverse rods 12 and disposed outside of but directly adjacent the innermost inside or first links 14.
The system can also include frictional (Figure 22) or positive (Figure 23) driving elements on the inside of the belt having vertical extending driving memhers 70 (Figures 19-21) for placing tension on the inner row o~
links 14' and 15'. One can also use a sprocket drive as in Figure 15.
This invention has been described in detail in connection with the illustra~ed pre~erred embodiments.
rrhese embodiments, however, are merely for example only and the invention is not restricted thereto. I,t will be ea~ily understood by those skilled in the art that other variations and modifications can be easily made within the scope o~ this invention, as defined by the appended claims.

~2~

,.~.~ ~ . .. .

Claims

1. A conveyor belt for conveying in both a straight line direction and around lateral curves in a single direction, the lateral curves having a predetermined maximum curvature with a predeter-mined radius of curvature, the conveyor belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adja-cent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means keeping the inside and outside ends of said rods at substantially the same first pitch dur-ing straight line motion of said belt and said link means further, dur-ing motion of the belt about said lateral curves, keeping said inside ends of said rods at substantially said first pitch and allowing said outside ends of said rods to move to a second greater pitch as the belt moves from straight line to lateral curved motion and to return to said first pitch as the belt moves from lateral curved to straight line motion, said link means including, along the inside concave edge of the belt, a plurality of separate inside links joining each pelf of adja-cent rods and, along the outside convex edge of the belt, at least one outside fink Joining each pair of adjacent rods, each of said outside links having holes through which said rods extend including at least one slot to allow the outside ends of said rods to move between the first and second pitches, each of said inside links including holes hav-ing end surfaces spaced a predetermined distance such that a plurality of said inside links joining adjacent rods aligns the, adjacent rods in a generally parallel relationship at said first pitch when said belt is placed under tractive load in straight line conveying motion.

2. A conveyor belt for conveying in both a straight line direction and around lateral curves in a single direction, the lateral curves having a predetermined maximum curvature with a predeter-mined radius of curvature, the conveyor belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adja-cent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said links means including, along the inside concave edge of the belt, at least two generally U-shaped inside links joining the inside ends of each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining the outside ends of each pair of adjacent rods, said generally U-shaped inside links each having a pair of spaced leg portions joined by a con-necting portion, each of said leg portions having holes for receiving said rods, each of said outside links having holes for receiving said rods, said holes in the legs of said inside links having end surfaces with a first predetermined longitudinal spacing, said holes in said out-side links having end surfaces with a second predetermined longitudi-nal spacing, said first and second longitudinal spacings being corre-lated to one another and to the predetermined radius of curvature so that in straight line conveying motion the inside ends of said rods are kept at a first pitch and the U-shaped inside links are tractive while the outside links are non-tractive, and during lateral curved convey-ing motion the inside ends of said rods are kept at substantially the first pitch and at least one of said U-shaped inside links remains trac-tive while the outside ends of said rods move to a second greater pitch.

3. A conveyor belt in accordance with claim 1 including at least one support link disposed adjacent said inside links and coupled between pairs of said adjacent rods, said support links including a lon-gitudinal portion extending both longitudinally between a pair of said adjacent rods and vertically away from said rods and at least one tab portion extending transversely from said longitudinal portion, holes being formed in said longitudinal portion through which an adjacent pair of rods extend, said tab portions being spaced a predetermined vertical distance from said rods to contact and support an inside edge of an adjacent vertically spaced tier of said belt when said belt is arranged to travel along a helical conveying path.

4. A conveyor belt in accordance with claim 2 including at least one support link disposed adjacent said inside links and coupled between pairs of said adjacent rods, said support links including a lon-gitudinal portion extending both longitudinally between a pair of said adjacent rods and vertically away from said rods and at least one tab portion extending transversely from said longitudinal portion, holes being formed in said longitudinal portion through which an adjacent pair of rods extend, said tab portions being spaced a predetermined vertical distance from said rods to contact and support an inside edge of an adjacent vertically spaced tier of said belt when said belt is arranged to travel along a helical conveying path.

5. A conveyor belt in accordance with claim 3 wherein said inside links include a pair of generally U-shaped links joining adjacent pairs of said rods with one of said U-shaped links being disposed on either side of a respective one of said support links each of said U-shaped links having a pair of spaced leg portions extending gener-ally in the lengthwise direction of the belt and a connecting portion joining said spaced leg portions, each of said leg portions having said holes of said inside links formed through it.

6. A conveyor belt in accordance with claim 4 or 5 wherein said spaced leg portions of said U-shaped inside links have end sec-tions adjacent to the longitudinal portions of said support links, and said end sections extending substantially perpendicular to the trans-verse extent of said rods to align said support links with respect to said rods.

7. A conveyor belt in accordance with claim 2 wherein said outside links include generally U-shaped links having a pair of spaces leg portions joined by a connecting portion.

8. A conveyor belt in accordance with claim 2 or 7 wherein said outside links include at least one bar link and have holes for receiving and coupling adjacent pairs of said rods.

9. A conveyor belt in accordance with claim 1 wherein each of said inside links has a work-hardened bearing surface.

10. A conveyor belt in accordance with claim 2 or 1 wherein said connecting portion of each of said U-shaped inside links has a work-hardened bearing surface.

11. A conveyor belt in accordance with claim 2 wherein the correlation between the longitudinally spaced end surfaces of the holes in said inside and outside links causes the outside ends of said rods to contact the opposing end surfaces in the holes of said outside links when the belt travels about a lateral curve of the predetermined maximum curvature with the outside links assuming a minimal amount of tractive load to assure that at least one of said inside links remains tractive and the inside ends of said rods remain at substantially the first pitch.

12. A conveyor belt in accordance with claim 11 wherein the ratio of the predetermined spacing between the holes of said out-side links to the distance from the center of the said predetermined radius of curvature to the outermost outside links is only slightly greater than the ratio of the predetermined spacing between the holes in said inside links to the distance from the center of the prede-termined radius of curvature to the outermost leg of said inside links.

13. A conveyor belt in accordance with claim 1 wherein said holes in said inside and outside links have end surfaces with predeter-mined longitudinal spacing correlated to one another and to the pre-determined radius of curvature so that in straight link conveying motion the inside ends of said rods are kept at the first pitch and the inside links are tractive while the outside links are non-tractive, and during lateral curved conveying motion the inside ends of said rods are kept at substantially the first pitch and at least one of the inside links remains tractive while the outside ends of said rods move to a second greater pitch.

14. A conveyor belt in accordance with claim 13 wherein the correlation between the longitudinally spaced end surfaces of the holes in said inside and outside links causes the outside ends of said rods to contact the opposing end surfaces in the holes of said outside links when the belt travels about a lateral curve of the predetermined maximum curvature with the outside links assuming a minimal amount of tractive load to assure that at least one of said inside links remains tractive and the inside ends of said rods remain at substantially the first pitch.

15. A conveyor belt in accordance with claim 14 wherein the ratio of the predetermined spacing between the holes of said out-side links to the distance from the center of the said predetermined radius of curvature to the outermost outside links is only slightly greater than the ratio of the predetermined spacing between the holes in said inside links to the distance from the center of the prede-termined radius of curvature to the outermost of said inside links.

16. A conveyor belt for conveying in both a straight line direction and around lateral curves in a single direction, the lateral curves including a helical path and having a predetermined maximum curvature with a predetermined radius of curvature in the helical path, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adjacent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means including at least two generally U-shaped inside links and a support link disposed along the inside edge of said belt, and at least one outside link disposed along the outside edge of the belt, said inside U-shaped links each having a pair of spaced leg portions connected by a connecting portion, each of said leg portions having holes for receiving adjacent ones of said rods, each of said outside links having holes for receiving adjacent ones of said rods, said support links having a longitudinal portion extending both longitudi-nally between a pair of said adjacent rods and vertically away from said rods and at least one tab portion extending transversely from said longitudinal portion, said tab portion being spaced a predetermined vertical distance from said rods to contact and support an inside edge of an adjacent vertically spaced tier of said belt when said belt trav-els along the helical path, said longitudinal portion of said support links having holes for receiving adjacent ones of said rods, said holes formed in said inside links having end surfaces with a first predeter-mined longitudinal spacing, said holes formed in said outside links having a second predetermined longitudinal spacing, said first and second longitudinal spacings being correlated to one another and to the predetermined radius of curvature such that in straight line con-veying motion the inside ends of said rods are kept at a first pitch and the inside U-shaped links are tractive while the outside links are non-tractive, and during lateral curved conveying motion the inside ends of said rods are kept at substantially the first pitch and at least one of the inside U-shaped links remains tractive while the outside ends of the rods move to a second greater pitch.

17. A conveyor belt in accordance with claim 16 wherein said outside links include generally U-shaped links having a pair of spaced leg portions joined by a connecting portion.

18. A conveyor belt in accordance with claim 16 or 17 wherein said outside links include at least one bar link having holes with said correlated predetermined second end surface spacing for receiving and coupling adjacent pairs of said rods.

19. A conveyor belt in accordance with claim 16 wherein each of said support links is disposed between a pair of said U-shaped inside links, said spaced leg portions of said U-shaped inside links have end sections adjacent to the longitudinal portions of said support links, and said end sections extending substantially perpendicular to the transverse extent of said rods to align the support links with respect to said rods.

20. A conveyor belt in accordance with claim 16 or 19 wherein said longitudinal portion of each of said support links has a lower section with said holes for coupling to said rods and an upper section extending vertically and longitudinally from the lower section, said upper section being angularly offset from the lower section and having a longitudinal dimension such that the upper sections of adja-cent support links overlap one another.

21. A tractive link member for connecting adjacent rods of an endless conveyor belt and for assuming tractive load, the links comprising a substantially flat piece of metal formed into a general U-shape with a pair of spaced leg portions joined by a connecting por-tion, each of said leg portions having at least one hole for receiving adjacent rods of a conveyor belt, said substantially flat piece of metal along the length of said connecting portion having both a first thick-ness area and a second, reduced thickness area, said reduced thickness area being a compressed work-hardened area of said metal, said reduced thickness area in said connecting portion forming a curved bearing surface against which a rod can bear.

22. A tractive link member in accordance with claim 21 wherein the second, reduced thickness of said work-hardened area of said connecting portion is reduced to at least 90% of the first thick-ness at the point of maximum reduction.

23. A tractive link member in accordance with claim 21 wherein said curved bearing surface has a curvature approximately the same as a rod to bear against said bearing surface.

24. A tractive link member in accordance with claim 21 wherein said link member is formed as a single integral U-shaped link.

25. A tractive link in accordance with claim 21 or 22 wherein said work-hardened area of said connecting portion has a substantially flat outer surface opposite said curved bearing surface.

26. In a conveying system including a conveyor belt and a drive means for moving the belt along a conveying path, said system orienting the belt in both a straight line direction and around lateral curves in a single direction, the lateral curves including a helical por-tion forming a plurality of stacked tiers of the belt and having a pre-determined maximum curvature with a predetermined radius of cur-vature in the helical portion, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adja-cent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means keeping the inside and outside ends of said rods at substantially the same first pitch dur-ing straight line motion of said belt and said link means further, dur-ing motion of the belt about lateral curves keeping said inside ends of said rods at said first pitch and allowing said outside ends of said rods to move to a second greater pitch as the belt moves from straight line to lateral curved motion and to return to said first pitch as the belt moves from lateral curved to straight line motion, said link means including, along the inside concave edge of the belt, a plurality of separate inside links joining each pair of adjacent rods and, along the outside convex edge of the belt, at least one outside link joining each pair of adjacent rods, each of said outside links having holes through which said rods extend including at least one slot to allow the outside ends of said rods to move between the first and second pitches, each of said inside links including holes having end surfaces spaced a prede-termined distance such that a plurality of said inside links joining adjacent rods aligns the adjacent rods in a generally parallel relation-ship at said first pitch when said belt is placed under tractive load in straight line conveying motion.

27. In a conveying system including a conveyor belt and a drive means for moving the belt along a conveying path, said system orientating the belt in both a straight line direction and around lateral curves in a single direction, the lateral curves including a helical por-tion forming a plurality of stacked tiers of the belt, and having a predetermined maximum curvature with a predetermined radius of curvature in the helical portion, the belt comprising a plurality of rods and connecting means for connecting said rods to form a length of the belt, said rods extending transversely of the length of the belt between an inside end along the inside edge of the lateral curves and an outside end along the outside edge of the lateral curves, said rods being arranged adjacent one another longitudinally along the length of the belt, said connecting means including link means disposed adja-cent said inside and outside ends of said rods for coupling adjacent pairs of said rods to one another, said link means including, along the inside concave edge of the belt, at least two generally U-shaped inside links joining the inside ends of each pair of adjacent rods, and, along the outside edge of the belt at least one link joining the outside ends of each pair of adjacent rods, said generally U-shaped inside links each having a pair of spaced leg portions joined by a connecting por-tion, each of said leg portions having holes for receiving said rods, each of said outside links having holes for receiving said rods, said holes in the legs of said inside links having end surfaces with a first predetermined longitudinal spacing, said holes in said outside links having end surfaces with a second predetermined longitudinal spacing, said first and second longitudinal spacings being correlated to one another and to the predetermined radius of curvature so that in straight line conveying motion the inside ends of said rods are kept at a first pitch and the U-shaped inside links are tractive while the out-side links are non-tractive, and during lateral curved conveying motion the inside ends of said rods are kept at substantially the first pitch and at least one of the U-shaped inside links remains tractive while the outside ends of said rods move to a second greater pitch.

28. In a conveying system in accordance with claim 27 wherein said outside links include generally U-shaped links having a pair of spaced leg portions joined by a connecting portion.

29. In a conveying system in accordance with claim 27 or 28 wherein said outside links include at least one bar link having holes with said second predetermined correlated end surface spacing for receiving and coupling adjacent pairs of said rods.

30. In a conveying system in accordance with claim 26 or 27 including at least one support link disposed adjacent said inside links and coupled between adjacent pairs of said rods, said support links having tab portions spaced a predetermined distance from said rods to contact and support the inside edge of a superimposed vertical tier of said belt.

31. In a conveying system in accordance with claim 26 or 27 wherein said drive means includes a rotating driving member friction-ally engaging the inside edge of said belt in the helical portion.

32. In a conveying system in accordance with claim 26 or 27 wherein said drive means includes a rotating driving member posi-tively engaging the inside edge of said belt in the helical portion.

33. A conveyor belt for conveying in both a straight line direction and around lateral curves comprising:
a plurality of rods extending transversely of the length of the belt, having first and second transverse ends, said rods arranged adjacent one another longitudinally along the length of the belt; and means for connecting said rods to form a length of the belt including link means, disposed approximately adjacent said first and second transverse ends of said rods for coupling adjacent pairs of each of said rods to one another, for holding the first and second transverse ends of each of said rods at a substantially same first pitch during straight line motion of said belt, for holding the transverse ends of each of said rods located at the inside concave edge of a lat-eral curve to the first pitch during motion of the belt about the lat-eral curve, for moving the opposite transverse ends of each of said rods to a second greater pitch along the outside convex edge of the lateral curve as the belt moves from straight line to lateral curved motion, and for returning the opposite transverse ends of each of said rods to the first pitch as the belt moves from lateral curved to straight line motion.

34. A conveyor belt in accordance with claim33 for travel around lateral curves in a single direction, wherein said conveyor belt connecting means link means further comprises:
a plurality of single pitch links disposed approximately along the inside edge of the belt having holes for receiving the first transverse ends of said rods during substantially all motion of the belt;
and a plurality of dual pitch links disposed approximately along the outside edge of the belt, said dual pitch links being capable of pivoting motion between a first position and a second position with the second transverse ends of said rods being disposed at the first pitch in the first position of said dual pitch links and the second transverse ends of said rods being disposed at the second pitch in the second position of said dual pitch links.

35. A conveyor belt in accordance with claim 34 wherein each of said dual pitch links include a body having a pivot aperture about which the dual pitch links can pivot and a pitch changing slot, the second transverse end of one of said rods being received in said pivot aperture and the second transverse end of an adjacent one of said rods being slidably received in said pitch changing slot, said pitch changing slot having a first pitch area where the second transverse end of said adjacent one of said rods is received when the rods are spaced by the first pitch and a second pitch area where the second transverse end of said adjacent one of said rods is received when the rods are spaced by the second pitch.

36. A conveying system using a conveyor belt in accordance with claim 34 the system including means for pivoting said dual pitch links between said first and second positions.

37. A conveying system in accordance with claim 36, wherein said means for pivoting includes a cam surface for engaging said dual pitch links.

38. A conveyor belt in accordance with claim 33 for travel around curves in both right and left directions, wherein said conveyor belt link means further comprises dual pitch links disposed approxi-mately along both edges of the belt, each of said dual pitch links being capable of pivoting motion between a first position and a second posi-tion, wherein during straight line motion said dual pitch links along both edges of the belt are in the first position for holding the trans-verse ends of said rods connected by the respective dual pitch links at the first pitch, and during motion around a lateral curve said dual pitch links along the inside edge of the belt being capable of remain-ing in the first position to hold the transverse ends of said rods con-nected by the respective links at the first pitch and said dual pitch links along the outside edge of the belt being capable of pivoting motion between a first position and a second position with the oppo-site transverse ends of said rods being disposed at the second pitch in the second position of said dual pitch links.

39. A conveyor belt in accordance with claim 38 wherein each of said dual pitch links includes a body having a pivot aperture about which the dual pitch links can pivot and a pitch changing slot, the transverse end of one of said rods being received in said pivot aperture and the transverse end of an adjacent one of said rods being slidably received in said pitch changing slot, said pitch changing slot having a first pitch area where the transverse end of said adjacent one of said rods is received when the rods are spaced by the first pitch and a second pitch area where the transverse end of said adja-cent one of said rods is received when the rods are spaced by the sec-ond pitch.

40. A conveying system using a conveyor belt in accordance with claim38 the system including means for pivoting said dual pitch links between said first and second positions.

41. A conveying system in accordance with claim 40 wherein said means for pivoting includes a cam surface for engaging said dual pitch links.

42. A conveying system comprising:
means for moving a conveyor belt in a straight line direction and around lateral curves in at least one direction;
a conveyor belt including:

a plurality of rods extending transversely of the length of the belt, each rod having first and second transverse ends, said rods arranged adjacent one another longitudinally along the length of the belt; and a plurality of links connecting said rods to form the length of belt, said links disposed approximately adjacent said first and second transverse ends of said rods for coupling adjacent pairs of said rods to one another, said links holding the first and sec-ond transverse ends of said rods at a substantially same first pitch during straight line motion of said belt, and during motion of the belt about a lateral curve holding the transverse ends of said rods located at the inside edge of the lateral curve to the first pitch, moving the opposite transverse ends of said rods to a second greater pitch along the outside edge of the lateral curve as the belt moves from straight line to lateral curved motion and returning the opposite transverse ends of said rods to the first pitch as the belt moves from lateral curved to straight line motion, said links including dual pitch links disposed approximately along at least one transverse edge of said belt, each of said dual pitch links including a body having a pivot aperture and a pitch changing slot, the transverse end of one of said rods received in said pivot aperture and the transverse end of an adjacent one of said rods being slidably received in said pitch changing slot, said pitch changing slot having a first pitch area where the transverse end of said adjacent one of said rods is received when the rods are spaced by said first pitch and a second pitch area where the trans-verse end of said adjacent one of said rods is received when the rods are spaced by said second pitch; and means for pivoting said dual pitch links between their first and second positions when said belt is driven past said pivoting means.

43. A conveying system in accordance with claim 42 wherein said belt is arranged to travel around lateral curves that include a helical portion forming a plurality of stacked tiers of the belt.

44. A conveying system in accordance with claim 42 wherein said belt is arranged to travel around lateral curves in both directions and said dual pitch links are located adjacent both transverse ends of said roads.

45. A conveyor belt including a plurality of rods extending transversely of the length of the belt between inside and outside edges of the belt, a plurality of first links disposed adjacent inside ends of said rods, and a plurality of second links disposed adja-cent outside ends of said rods, the improvement comprising:
each of said first links coupling adjacent rods to each other near the inside edge of said belt;
each of said second links coupling adjacent rods to each other near the outside edge of said belt; and said belt constructed for holding said inside ends of said rods at a first pitch rela-tive to each other during straight-line travel of said belt, for holding said inside ends of said rods at said first pitch relative to each other during curved travel of said belt and for allowing said outside ends of said rod to move to a second greater pitch relative to each other during said curved travel of said belt.

46. A conveyor belt as in claim 45, further comprising means, interconnected to said adjacent rods and disposed outside of but directly adjacent said first links, for assuring that said rods extend substantially parallel to each other during straight-line motion of said belt.

47. A conveyor belt as in claim 46, wherein said assuring means further com-prises a plurality of third links coupling adjacent rods to each other.

48. A conveyor belt as in claim 47, wherein, during straight-line conveying motion, said first and third links are tractive while said second links are non-tractive and, during lateral curved conveying motion, at least said first or said third links remain tractive.

49. A conveyor belt as in claim 47, wherein said first and third links are sub-stantially U-shaped links joining inside ends of adjacent rods, each of said U-shaped links having a pair of spaced leg portions extending generally in a lengthwise direction of the belt and a connecting portion joining said spaced leg portions, and each of said leg portions having holes formed therethrough for receiving inside ends of said rods.

50. A conveyor belt as in claim 45, for use in a system having a straight-line loading section, a helical path section and a straight-line discharging section, and said belt constructed for bending from a horizontal to a vertical direction and vice versa about a direction changing mechanism.

51. A conveyor belt as in claim 50, wherein said second links include at least one bar link having holes for receiving and coupling adjacent pairs of said rods.

52. A conveyor belt as in claim 50, wherein each of said first links have holes with end surfaces spaced a predetermined distance apart and said holes are slightly oversized with respect to the cross-dimensional width of said rods.

53. A conveyor belt as in claim 45, being arranged in a system to define a straight-line loading section, a helical path section and a straight-line discharging sec-tion, said system further comprising:
means for driving said conveyor belt so that said belt follows along said straight-line loading section and then along said helical path section; and means, disposed along and in contact with one of said straight-line sec-tions of said system, for bending said belt from a horizontal direction to a vertical direction and vice versa.

54. A conveying system as in claim 53, wherein said helical path section forms a plurality of stacked tiers of the belt and said system further comprises at least one support link disposed adjacent said first links and coupled between adjacent pairs of said rods, said support link having tab portions spaced a predetermined distance from said rods to contact and support the inside edge of a superimposed vertical tier of said belt.

55. A conveying system as in claim 53, wherein said bending means further comprises a pulley disposed along a straight-line section of said system.

56. A conveyor belt as in claim 45, being arranged in a system to define a straight-line loading section, a helical path section and a straight-line discharging sec-tion, said system further comprising:
means for driving said conveyor belt so that said belt follows along said straight-line loading section and then along said helical path section; and means, disposed along and in contact with one of said straight-line sec-tions of said system, for guiding said belt directly from said straight-line discharging section to said straight-line loading section.

57. A conveying system as in claim 56, wherein said belt guiding means fur-ther comprises one of pulleys, rollers, sprockets, and vertical hanging take-up mecha-nisms.

58. A conveying system as in claim 56, wherein said belt guiding means also adds tension to said belt.

59. A conveying system as in claim 56, wherein said belt driving means includes a rotatable drum mounted to rotate about a vertical axis, said drum including an outer surface which engages inner lateral edge regions of said belt.

60. A conveying system as in claim 56, wherein said belt driving means includes an internal rotating cage having a plurality of vertically extending driving members.

61. A conveying system as in claim 56, wherein said belt driving means drives said belt by relatively low tension.

62. A conveying system as in claim 569 wherein said belt guiding means fur-ther comprises means for flipping said belt over as it moves from said straight-line discharging section to said straight-line loading section.

63. A conveying system as in claim 56, wherein inside belt edges along said straight-line loading section and inside belt edges along said straight-line discharging section are both disposed on a generally vertical plane that lies tangential to said heli-cal path section.

64. A conveyor belt as in claim 45, wherein:
said first links holding said inside ends of said rods at a first pitch relative to each other during both straight-line and curved travel of the belt; and each of said second links have a longitudinal slot receiving one of said transverse rods near the outside end of said rod, said slots being of sufficient length to allow the outside ends of said rods to move to a second greater pitch relative to each other during curved travel of said belt.

65. A conveyor belt as in claim 64, further comprising:
means, extending around adjacent transverse rods, for assuring that said adjacent rods extend substantially parallel to each other during straight-line travel of said belt.

66. A conveyor belt as in claim 65, wherein, during straight-line conveying motion, said first links and said assuring means are tractive while said second links are non-tractive and, during lateral curved conveying motion, at least said first links or said assuring means remain tractive.

67. A conveying belt as in claim 45, in a system having a helical path portion with upper and lower end portions at vertically opposite ends thereof wherein:
said belt enters one of the end portions of the helical path portion of said conveying system and exits the other of the end portions of the helical path portion of said conveying system;
while said belt moves from said helical path exit to said helical path entrance said rods stay at a substantially constant first pitch relative to each other near both the inside and outside edges of said belt; and when said belt moves along the helical path portion of said conveying system, said first links hold said inside ends of said rods at a first pitch relative to each other and said second links allow said outside ends of said rods to move to a second greater pitch relative to each other.

68. A conveying system as in claim 67, further comprising means for flipping said belt over as it moves from said helical path portion exit to said helical path portion entrance.

69. A conveying system as in claim 45, wherein the ratio of an inside turn radius of said belt on said helical path to a width of said belt is less than 1.4 to 1.

70. A conveyor belt as in claim 45, wherein said first links include:
two leg portions and a connecting portion joined to each of said two leg portions;
said connecting portion and each of said two leg portions define a gener-ally U-shaped link member; and said connecting portion includes:

a first thickness area; and a second, reduced thickness area, said reduced thickness area being a compressed work-hardened area which has a surface against which one of said rods can bear.

71. A conveyor belt as in claim 70, wherein each of said leg portions of each of said first links further comprise an outwardly diverging section.

72. A conveyor belt as in claim 71, wherein each of said leg portions of each of said first links further comprise:
an inner section disposed between the connecting portion and the out-wardly diverging section and said inner section having a hole for receiving one of said rods of the conveyor belt which can bear against the reduced thickness area in the con-necting portion; and an outer section extending from the outwardly diverging section and hav-ing a hole for receiving an adjacent rod.

73. A conveyor belt as in claim 72, wherein said outer section of each leg portion is generally parallel to said inner section and said outwardly diverging section forms a single offset between the generally parallel inner and outer sections of the legs.

74. A conveyor belt as in claim 71, wherein each of said leg portions of each of said first links further comprise:
an inner section disposed between said connecting portion and the out-wardly diverging section and extending generally perpendicular from the connecting portion; and an outer section extending from the outwardly diverging section in a direction generally parallel to the inner section.

75. A conveyor belt as in claim 74, wherein each of said inner sections of each of said leg portions have a hole for receiving a rod of the conveyor belt to be dis-posed against the work-hardened area of the connecting portion and each of said leg portion outer sections have a hole for receiving an adjacent rod of the conveyor belt.

76. A conveyor belt as in claim 45, further comprising a support link disposed generally along the inside edge of said belt, said support link including:
a generally upright, longitudinal portion having upper and lower portions, said lower portion including at least one transverse opening means for receiving therein at least one of said rods; and first and second support tab portions extending out from said upper por-tion in opposite transverse directions.

77. A conveyor belt as in claim 76, wherein said lower portion of said support link is longitudinally narrower than said upper portion.

78. A conveyor belt as in claim 76, wherein said opening means of said sup-port link lower portion defines first and second openings for first and second rods.

79. A conveyor belt as in claim 76, wherein said first and second tab portions of said support link are spaced in a longitudinal direction.

80. A conveyor belt as in claim 76, wherein said upper portion of said support link includes a slot disposed between said first and second tab portions.

81. A conveyor belt as in claim 76, wherein said upper portion of said support link is angularly offset from said lower portion.

82. A conveyor belt as in claim 76, wherein said upper portion of said support link is angularly offset from said lower portion by approximately four degrees.

83. A conveyor belt as in claim 76, wherein said longitudinal portion of said support link necks down from said upper portion to said lower portion.

84. A conveyor belt as in claim 76, further comprising means, extending around adjacent rods, for assuring that said rods extend substantially parallel to each other during straight-line motion of said belt, and wherein said support link is disposed adjacent said first links and said assuring means and is coupled between pairs of said adjacent rods, said support link longitudinal portion extends both longitudinally between a pair of said adjacent rods and vertically away from said rods, and said tab portions being spaced a predetermined vertical distance from said rods to contact and support an inside edge of an adjacent vertically spaced tier of said belt when said belt is arranged to travel along a helical conveying path.

85. A conveyor belt as in claim 84, wherein said first links and said assuring means are U-shaped links with one of said U-shaped links being disposed on either side of said support link.

86. A conveyor belt as in claim 85, wherein said U-shaped links further com-prise a pair of spaced leg portions extending generally in the lengthwise direction of the belt and a connecting portion Joining said spaced leg portions, and said spaced leg portions of said U-shaped links have end sections adjacent to the longitudinal portion of said support link with said end sections of said links extending substantially perpendicu-lar to the transverse extent of said rods to align said support link with respect to said rods.

87. A support link as in claim 76, wherein said upper section has a longitudi-nal dimension such that upper sections of adjacent support links can overlap one another.